Automatic controller for refrigerating systems



June-17, 19305 i L. BRLuzi-n.-.- i' i i 1 AUTOHA'IIC CONTROLLER FqREFRIGBRATING sYsTE'us'- l `1=i11aauu1 1112,um,

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" ATTORNEYS www4 Patented .lune 17, 1930 UNITED STATES.PnTaNlol-Fljcl-I.

LAWRENCE BRUEHL, OF BROOKLYN, vNEW YORK,..ASSIGNOR TO'GAS REFBIGEBATIONI CORPORATION, F SCBANTON, PENNSYLVANIA', LA. COBPORATION OF DELAWARE`AUTOMATIC coirraomlnn Foa REFBIGEBA'TING sYsTEms Application led .Tune2, 1927. Sel'iel No. 195,984.

This invention relates to the means employed for cont-rolling theheating medium of a refrigerating apparatus -of the intermittentlyoperating absorption type.

=| Although it may be employed where the condenser and absorber arecooled by water and other regulating means are employed for controllingthe flow of water, it is particularly intended for apparatuses of theair cooled 20 In Fig. 1 I have'shown a construction in which twoseparate and independent controlling valves'are employed inseries in theconductor for the heating medium; and In Figs. 2 and 3 I have shown two.other forms in each of which only a single valve is used.

- In the form shown in Fig. 1 there is a conductor for .the heatingmedium. This is illustrated as a pipe which may serve to 3o conductcombustible gas, steam, hot oil, or any other suitable fiuid heatingmedium, but an electric conductor would be used if electricity were theheating medium. In this conductor there is a pair of valves 11 and 12for controlling the iiow of the heating m'edium. Within the broadmeaning of the term valve I include a switch .or other means suitablefor controlling .an electric heating current.

Within the evaporator 13 or associated in heat interchangingrelationship thereto, there is employed a cell or tube 14 for a Huid medium which will expand and contract with the changes in temperature inthe evaporator and this is connected to the valve 11 by suitableoperating mechanism.

In the boiler-absorber 15 there is employed a similar cell or tube 16for operating the valve 12.

The mechanism for operating the two valves may. be similar and thatillustrated is constructed and operated as follows:

The valve stern 17 intermediate of. its ends .engages a lever 18 whichis pivoted in one end of the-valve casing 19. Also within the casingthereis a bellows 20 which forms a partition subdividing the chamberinto two compartments. The end wall 21 of the diaphragm is pivotedbymeans of a lug 22. At A l one side of the center and projecting inwardlyfrom the center is a pin 24. The pin 24 and the lever 18'areindependentlymovable and are capable of being brought into axialalignment. Between the-two .is a coil spring 25 which tends to pressthem in opposite' directions and serves to snap the valve to open orclosed position. Each valve casing has connections whereby it may besecured in series in the conductor for heating medium and each valve hasan adjustable stop 26 whereby the opening movement ofthe valve may belimited. The heating medium may fill the portion of the casing. aroundthe spring 25 and above the bellows, while the cell-14 is connected by aconduit 27 to the compartment of the valve casing below or outside ofthe bellows. The expansion and contraction of the .fluid medium in thecell causes varying .pressure on the bellows and' will operate tocollapse or contact the bellows under high pressure and permit thebellows to expand at low pressure.

The end wall of the bellows being pivoted at one "side, the upper end ofthe pin 24 will move back and forth to opposite sides of the 'lower endof the lever 18.

The operation of the construction illustrated is substantially asfollows:

The parts ,are shown in such position that thetwo valves are open. Thisis the position the parts are to occupy at the beginning of the heatingperiod. There is comparatively low temperature in the boiler-absorber as-the gas is passing off freely to the condenser and there is acompara-tively high temperature in the evaporator as there is noevaporation or cooling effect taking place.` As the heating of theboiler-absorber continues the operatlon will reach a point at whichsubstantiallyall of the ammonia or other refrigerant gas has been driven0H, and the temperature will rise to such a point in the boilerabsorberthat the uid in the cell 16 in expanding will exert sufiicient pressureon the bellows of the valve 12 to collapse the latter and swing the pin24 from the position indicated, toward the right to such a point that itwill pass the axis of the lever 18. The spring 25 will then instantlymove the lever 18 to the opposite limiting position and close the valve12. The supply of heating medium of the boiler-absorber Will thus stopeven though the valve 11 is open. The temperature of the boiler-absorberwill then begin to drop and evaporation in the evaporator will begm. Y

As the evaporator temperature drops the pressure thermostatic medium inthe cell 14 will decrease and the bellows 20 of the valve 11 will expandto swing the pin 24 toward the right and close the valve 11.

The cooling of the boiler-absorber will also cause the contraction ofthe thermostatic medium in the cell 16 and the pin 24 of the valve 12will swing tothe left and open the valve 12. The parts are so adjustedthat the valve 11 will close before the valve 12 opens and therefore theopening of the valve 12 does not turn on the heat-ing medium. The

operation will continue with the valve 11 closed and the valve 12 open,until the refrigerating medium in the evaporator is all evaporated orthe absorbent in the boilerabsorber cannot absorb any more of therefrigerant. The temperature of the evaporator will then increase tosuch a point that the pin 24 will again swing toward `the left and snapthe valve 11 to open position. As the valve 12 is already open theheating medium will be turned on.

Obviously the tem erature range of the boiler-absorber will e very muchgreater than that of the evaporator and therefore the size of the cellsfor the thermostatic medium, the strength of the diaphragm, the relativeproportion of the parts, etc. may be varied to effect the opening andclosing of the valves at the desired temperatures. For instance, theparts may be designed so that the valve 11 will open when the evaporatortemperature reaches 31 F. and will close at 27 F., while the valve 12will open when the boiler-absorber gets down to 130 F. and will `closeat 260 F. Obviously the boiler-absorber may reach a temperature verymuch below 130 F., and the evaporator may reach a temperatureconsiderably above 31 F.

The heating starts when 'the evaporator temperature reaches its highlimit of 31 F. and the heating stops when the boiler-absorber reachesits high limit of 260 F.

Of course, the apparatus may be adjusted so that the controllingtemperatures are higher or lower than those above mentioned. Thisadjustment may be secured by the adjusting screws 26. These limit theextent to which the valves may be opened and therefore control theextent to which the pins 24 are moved toward the right before the valvessnap shut.

From a manufacturing standpoint, preferably the mechanism for operatingthe two valves 11 and 12 is identical, although in assembling, thepivotal support 22 for one valve is placed at one side ofthe casing andfor the other valve it is placed at the opposite side of the casing. Thetemperature range is preferably controlled by the character and quantityof the thermostatic uid employed in the cells 14 and 16.

' It will be noted that the apparatus is foolproof and self-starting, inthat it automatically takes care of any abnormal operating condition andautomatically returns to normal working condition. If the heating mediumbe shut off at some other point in the line the temperature in theevaporator will rise above 31 F. to open the valve 11 and thetemperature in the boiler-absorber will drop below 130 F. to openthevalve 12. Therefore, when the heating medium is again turned on, bothvalves will be open to start a new cycle of operations. If the heatingmedium be combustible gas, there will, of course, be provided anautomatic safety ilot light which will insure the lighting o the gaswhen it isturned on.

As the valve casing and operating mechanisms for the valves 11 and 12are entirely independent, it will be evident that they may be placed atseparate points in the conductor 10, and either directly adjacent toeach other or spaced to any distance apart.

In the construction shown in Fig. 2 a single valve 30 is employed forthe heating medium. Two separate thermostatie power elements areemployed which may be similar to those shown in Fig. 1, but they arebothoperatively connected to this single valve. In-

fstead of using fluid thermostatic power elements, I have .illustratedexpansible rods. A tube 31 is connected to the valve casing 32 andwithin it is a rod 33. The rod and tube are connected together at theouter end and they are of such material as to have differ- *entcoeiicients of expansion. On the oppo- -site side of the casing 32 thereis a similar tube 34 with its expansible rod 35. Preferaybl the tube 31extends into the boiler while the tube 34 extends'into the evaporator.

i The inner ends of the rods are threaded or provided with rack teeth,and they are spaced apart and in engagen'lent with opposite sides `of aroller or pinion 36. The endwise movement of either rod will cause therotation of the pinion. The pinion has a lever arm 37 which engages oneend of the Ispring 38. The opposite end of the spring is connected to alever 39 which is pivoted intermediateof its. ends and serves to operatethe valve 30.

The operation of this apparatus is as follows:

At the end kof the absorptionperiod the i boiler-absorber is cooled andthek end of the ing screw 40. This is because the tube 31 has rod 33 isat the extreme position toward the right, that is in engagement with theadjustswing toward the right to a point beyond the end of the rod 35serves to regulate the tem? axial projection of the lever 39. Thereuponthe spring causes the valve 30 to snap to open position. As the boilerwarms up the rod 33 movestowardthe left and swings the lever 37 in theopposite direction. lVhen the temperature of the boiler reaches thepredetermined point the lever 37 will then swing over to such a pointthat it comes to the opposite side of the axial projection of the lever39 and the valve 30 snaps to closed position. The time of this movementis modified dueto the fact that the absorber is also warming up at thesame time. The screw 41 opposite the perature of the boiling period andto keep this temperature fixed at a certain, point. During the latterpart'of the boiling period tlie rod 35 rests against the screw 41. The

rod 33 is still free to move toward the .left so that the lever 37 turnscounterclockwise uny til the valve plunger is shifted and the heatingmedium is shut o. Now both rods start to move to the right and theirspeeds are proportional to the decrease in temperature of reverses itwhen the rod 33 reaches the regulati-n screw 40. As the rod 33 cannotmove any urther, but, the rod 35 can, the lever 37 will be eventuallymoved to such position that the lever is again shifted and the nextboiling period begins.

The operation of this mechanism is also completely fool-proof. If theevaporator is under an overloadthe temperature in the evaporator willnot go down far enough to move the rod 35 from its rest position on thescrew 41. In this case the rod 33 swings the lever 37 to start the nextboiling period and the length of the cycle is a function of the rate ofboiler radiation. Under such overload conditions the control of themachine is solely by the power element of the boiler. The machine may beshut down at any point in the cycle and the mechanism will automaticallybring the valve 30 to open position to start a new heating period whenthe apparatus is permitted to start operatin again. Themovement yof therods 33 an 35 are parallel and in the same direction with increasingtemperature.

Another construction operating on this principle is shown in Fig. 3.Here there are employedtwo bellows 42 and 42a. mounted in casings 43 and44 and connected to rods 45 and 46. The two casings may be secured to asupporting wall 47 and the two rods may be connected by a link 48. Theconnection 'zeA should be such as permits a sliding atl one i end or theother. As shown the link 48 is connected to the rod by a pivot pin 49and to the rod 46 by a slot 50and pin 51. The rodv i bellows there aresprings 59 tending to expand them against action of the thermostaticpower fluids. yThe tube 57 is connected to the thermostatic element inthe boiler, while the tube 58 is connected to the thermostatic elementof the evaporator. The link 48 is connected in any suitable manner tosuch a valve as that shown in Fig. 2. The link is illustrated as havinga bail 60 secured thereto intermediate of its'ends and having a portionprojecting into engagement with a spring 38. This spring serves tooperate a valve lever 39 and valve 30 which may be substantially thesame as shown in Fig. 2.

The operation is as follows:

i The p arts are shown in the position which they occupy during thelatter part of the absorption period. The bellows 42 lis in a fixedposition because the stop 52 is in engagement with thel guide 53. Theevaporator contains no liquid refrigerant and is not generating any morecold so that the temperature increases and the bellows 42a contracts.

'At a certain point corresponding with the desired temperature, thebellows will reach such a position that the valve is shifted and theboiling starts. Now both of the rods 45 and 46 move outwardly, butaftera short time the travel of therod 45 is stopped because the bellowsrests against the lower 4end of the bushing or stop 54. The rod 46 willcontinue to move outwardly `to swing the link 48 and the bail 60 untilat the end of the boiling period the valve 30 is shifted to closedposition. The absorption period now starts and the rod 46 moves backinto thecasing 43 as the temperature in the boiler decreases. A shorttime later when the cold is generated in the evaporator the rod 45 alsomoves back. By the back movement, the valve lever is not shifted and thevalve remains closed. Should the rod 45 fail to go back due overload inthe evaporator, the rod 46 would serve to swing the link 48 and open thevalve for the start of a new boiling period. The tempera.- ture may beregulated by the adjustment of the nut 52 and the bushing 54. The valvemay be placed in any desired position in respect to the link 48 so thatthe tilting 'of the link moves the end of the spring 38 over the desiredrange. The bail (50 may extend downwardly from the link, or as shown indotted lines a projection may extend upwardly from the llilik anddirectly to the spring v of a valve disposed above.-

the boiler-absorber, a pair of separate identic movable fluid pressureoperated member, re-

silient connections between said member and the valve for holding thelatter in either closed or full open position, and adjustable means forlimitingl the opening movement, means for moving the member of one ofsaid valves in accordance with the temperature in the evaporator, andmeans for moving the otherof said members in accordance with the.temperature in the boiler-absorber.

2. A refrigerating apparatus of the interture in the boiler-absorber andthe evaporator. v

4. A refrigerating apparatus of the inter.- mittently operatingabsorption type, including a conduit for supplying heating medium, valvemechanism for controlling said conduit, a pair of containers 'forexpansible fluid, one disposed in thermal connection with the evaporatorand the other in thermal connection with the boiler-absorber, a pair of.valve operating members, one moving in accordance with the pressure inone of said containers and the other movable in accordance with thepressure in the other container, and reversible snap connections betweensaid valve mechanism and said members.

Signed at New York in the county of New York and State of New York this2 lst day of May A. D. 1927.

LAWRENCE BRUEHL.

mittently operating` absorption type, including a conductor for theheating medium for interchangeable Valves in said conductor forcontrolling the supply ot' the heating medium, each of said valves beingprovided with a movable fluid pressure operated member and resilientconnections between said member and the valve for holding the latter ineither closed or full open position, means formoving the member of oneof said valves in accordance with the ten'lperature in the evaporator,and means for moving the other of said members in accordance with thetemperature in the boiler-absorber.

3. A refrigerating apparatus of the intermittently operating absorptiontype having a conduit for supplying heating medium to theboiler-absorber, a pair of separate and independent reciprocating valvesin series in said conduit, a pair of expansible bellows, snapconnections between each bellows and its corresponding valve for movingthe valve to either of its two opposite limiting positions,

an expansible iinid container in thermal connection with the evaporatorand connected to one bellows, and a similar expansible fluid containerin the boiler-absorber and connected to the other bellows whereby theheating medium is controlled solely by the tempera-

